The present disclosure relates to a power amplification module.
A power amplification module is used in a mobile communication device such as a cellular phone in order to amplify the power of a radio frequency (RF) signal to be transmitted to a base station. For example, in the global system for mobile communications (GSM) (registered trademark), the gain of a power amplification module is controlled in order to realize slope control (ramp up and ramp down) for a transmission signal to be transmitted from a mobile communication device to a base station.
In Japanese Unexamined Patent Application Publication No. 2009-100197, a configuration is disclosed in which a voltage Vldo output from a low drop out (LDO) regulator is supplied to a collector terminal of each stage of a 3-stage amplifier in a power amplification module. In this configuration, the gain of the power amplification module is controlled by adjusting the level of the voltage Vldo on the basis of a level control voltage Vramp.
In addition, in U.S. Pat. No. 7,605,651, a configuration is disclosed in which a voltage Vreg output from an LDO regulator is supplied to first and second stages and a constant power supply voltage is supplied to a third stage in a power amplification module including a 3-stage amplifier.
In the configurations disclosed in Japanese Unexamined Patent Application Publication No. 2009-100197 and U.S. Pat. No. 7,605,651 described above, an LDO regulator is used in order to control the gain of a power amplification module. Generally, in order to supply a large current, the circuit scale of an LDO regulator is large.